You might want to update the links here. Had this issue but both links are down; the first one is 404'd and the second is blocked by mediafire for being malicious. (Thankfully, Silver sent it to me over discord).

Personally I wouldn't take a bright red page with a white-background JPEG very seriously in this case... Especially since I haven't seen anything similar or anyone else complain.
If you haven't already managed to fix it, try running Malwarebytes Junkware Removal Tool and/or AdwCleaner and/or Malwarebytes itself (All three should be a pretty easy find with google) and see if that helps.
If it's already fixed, then at least you don't have to worry anymore.

It's in the New World Town of Eclage, in a tower somewhere. I'm not sure if it's implemented into RRO (it is a part of New World, which we have) but to be honest, I'm too lazy to check if the quests are available. For iRO you need to do the Wandering Guardian Quest inside Hazy Forest for access to Mora Village. Then exit through the east entrance in Mora and ask the cat hand NPC to warp you "Near Eclage". Then to my knowledge you have to do the Entrance Quest to actually get inside.

For bugs, you should report them here. I'm willing to bet you can sign up for helpdesk in-game and talk to a GM about it, tell them you reported it on the bug tracker, and get your glasses back (though you'll probably need some kind of proof, not sure if NPCs like that keep a log of any kind).

Normal PC, I haven't been able to not use this wallpaper for the past two years, it's just SO GOOD.
I absolutely love overgrown places, green is so pretty <3 Alt. Desktop (Dualboot / Liveboot from USB)
Arch Linux with Budgie DE with Arc Flatabulous Darker widget theme and Paper Icon & Cursor theme
I like to keep it clean since absolutely everything is all neat and organized in the start menu (Thank you, Alacarte)

So, turns out I don't really play this game. The last time I opened it was two months ago; and before that, probably a year or something. At least 6 months.
Anyways, I have a bunch of stuff that honestly I didn't even know I had, let alone use at all, as well as stuff I spent way too much money on. I'm going through some early spring cleaning and selling a bunch of stuff. I would RMT it all, but I can't, since we're only allowed to trade credits and I don't even have the minimum required amount of posts to put anything there. So this should fix both of those. Prices are up in the air, just make them reasonable. Contact me either on forums or in game, using the same name (Mama Florist) if I'm online.
--> Weapons and Gear <--
Poring Book [1]
+10 Freezing Bow Upgraded [3] (aka "Frozen Bow [3]" )
+9 Goblin Revolver [2]
--> Cards <--
Bacsojin Card (x3)
Gemini-S58 Card (x2)
General Egnigem Card
High Wizard Card
Kiel-D-01 Card
Orc Hero Card (x2)
Poring Blacksmith Card
Poring Hunter Card
Skoll Baby Card
Tao Gunka Card
Thanatos Card (x2)
Turtle General Card (x3)
--> Other <--
SRT Box

You might want to try updating again if @go 16 still sends you to the jail.
If that doesn't work, there are still two other ways to get there that I know of, at least on Loki. You can either go to @go 9 (Yuno) and talk to the 'Mall' NPC just under where you spawn, or you can walk to the building by heading to the northern part of Morroc, east of the Kafra Employee (190,256). There's a character storage NPC on the north-eastern corner of the mall, next to the chef area at the bottom of the stairs, and Battlegrounds rewards NPCs are in to north-west corner assuming the layout of the mall is the same, which I don't really see why it wouldn't be..
I imagine there's a chance of you not having the actual files for the mall's new map if you don't have the @go command, though, so be prepared to reset your location on the website if you error out.